Dental plaque is a soft deposit which forms on the surfaces of teeth. Dental plaque is generally believed to be formed as a byproduct of bacterial growth and comprises a dense microbial layer consisting of a mass of microorganisms embedded in a polysaccharide matrix. Plaque tenaciously adheres to the surfaces of teeth, especially along irregular and rough surfaces, and is typically found at the gingival margin, in cracks in the enamel, and on the surface of built-up dental calculus.
Gingivitis is the inflammation or infection of the gums and the alveolar bones that support the teeth. Gingivitis is generally believed to be caused by bacteria in the mouth (particularly the bacteria instigated in plaque formation) and the toxins formed as byproducts from the bacteria. Periodontitis is generally believed to occur where unremoved plaque hardens into calculus (tartar) which affects the periodontal ligaments. Periodontitis is a progressively worsened state of disease as compared to gingivitis. As plaque and calculus continue to build up, the gums begin to recede from the teeth and pockets form therebetween, which ultimately may result in destruction of the bone and periodontal ligament. These reactions lead to the destruction of the supporting structure, continued infection, and potentially the subsequent loss of teeth.
The plaque formed along the tooth surfaces thus provides a locus for calculus (tartar) formation. Dental calculus, or tartar, is a hard mineralized solid formed on the teeth when crystals of calcium phosphate are deposited in the pellicle and extracellular matrix of the dental plaque and become crystalline hydroxyapatite, sufficiently closely packed together for the aggregates to become resistant to deformation. Regular brushing aids in preventing a rapid build-up of these deposits, but even regular brushing is not sufficient to remove all of the calculus deposits which adhere to the teeth. While there is no complete agreement on the route by which precipitated calcium and orthophosphate ultimately become the crystalline material called hydroxyapatite (HAP), it is generally agreed that at higher saturations (above the critical saturation limit) the precursor to crystalline HAP is an amorphous or microcrystalline calcium phosphate. “Amorphous calcium phosphate” although related to hydroxyapatite differs from it in atomic structure, particle morphology, and stoichiometry. Agents which effectively interfere with crystalline growth of HAP will be effective as anticalculus agents. One suggested mechanism by which many anticalculus agents inhibit calculus formation involves an increase of the activation energy barrier thus inhibiting the transformation of precursor amorphous calcium phosphate to HAP. Studies have shown that there is a good correlation between the ability of a compound to prevent HAP crystalline growth in vitro and its ability to prevent calcification in vivo, provided that the compound is stable in and inert to other components in an oral care composition and to saliva in the oral cavity.
Thus, it is desirable to have an oral care composition that combats plaque by antibacterial activity and further controls and prevents calculus formation. It is difficult to predict the antiplaque efficacy of antibacterial compounds when incorporated in a delivery vehicle and particularly in oral compositions having other active ingredients, such as anticalculus (tartar control) agents. There is often a negative interaction between an antibacterial agent with other active ingredients or other components in a delivery vehicle of an oral care composition that reduces the effective performance of such oral compositions, including toothpaste and mouth rinses. This is especially true for many anticalculus systems.
In order to overcome these problems a tartar control oral care composition has hitherto been provided which contains an antibacterial active compound from an extract of magnolia and an anticalculus system comprising tetrasodium pyrophosphate and sodium tripolyphosphate. Active compounds extracted from magnolia include magnolol and honokiol which are antibacterial biphenol compounds. Tetrasodium pyrophosphate and sodium tripolyphosphate are anticalculus agents.
Notwithstanding the efficacy of certain antibacterial agents, there is a continuing interest in the oral care field for oral care compositions which improve the treatment of both plaque and tartar formation. Thus, there is a need for a highly effective antibacterial, antiplaque and anticalculus oral care composition to prevent or diminish oral care diseases.